I’ve found solution for you: in your TimerOnTick() you have to set your new value to the propper cell in real 2DArray to get text updated

[1] var values = ((IHeatmap2DArrayDataSeries)heatmapSeries.DataSeries).GetArray2D(); — this will return you a real collection [2] values[YAxis, XAxis] = newValue; — this will set your new value to the collection;